CVE-2024-31999: @festify/secure-session creates a secure stateless cookie session for Fastify. At the end of the request handling, it will encrypt all data in the ses...

Description

@festify/secure-session creates a secure stateless cookie session for Fastify. At the end of the request handling, it will encrypt all data in the session with a secret key and attach the ciphertext as a cookie value with the defined cookie name. After that, the session on the server side is destroyed. When an encrypted cookie with matching session name is provided with subsequent requests, it will decrypt the ciphertext to get the data. The plugin then creates a new session with the data in the ciphertext. Thus theoretically the web instance is still accessing the data from a server-side session, but technically that session is generated solely from a user provided cookie (which is assumed to be non-craftable because it is encrypted with a secret key not known to the user). The issue exists in the session removal process. In the delete function of the code, when the session is deleted, it is marked for deletion. However, if an attacker could gain access to the cookie, they could keep using it forever. Version 7.3.0 contains a patch for the issue. As a workaround, one may include a "last update" field in the session, and treat "old sessions" as expired.

Metrics

CVSS 3.1

7.4/10

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:N/A:N

EPSS Probability

0.62%

45.0th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-613

References

Timeline

Published: Apr 10, 2024
Last Modified: Jun 17, 2026
Status: Deferred

Frequently Asked Questions

What is CVE-2024-31999?

@festify/secure-session creates a secure stateless cookie session for Fastify. At the end of the request handling, it will encrypt all data in the session with a secret key and attach the ciphertext as a cookie value with the defined cookie name. After that, the session on the server side is destroyed. When an encrypted cookie with matching session name is provided with subsequent requests, it will decrypt the ciphertext to get the data. The plugin then creates a new session with the data in the ciphertext. Thus theoretically the web instance is still accessing the data from a server-side session, but technically that session is generated solely from a user provided cookie (which is assumed to be non-craftable because it is encrypted with a secret key not known to the user). The issue exists in the session removal process. In the delete function of the code, when the session is deleted, it is marked for deletion. However, if an attacker could gain access to the cookie, they could keep using it forever. Version 7.3.0 contains a patch for the issue. As a workaround, one may include a "last update" field in the session, and treat "old sessions" as expired.

How severe is CVE-2024-31999?

CVE-2024-31999 has a CVSS score of 7.4/10 (HIGH severity). The EPSS model estimates a 0.62% probability of exploitation in the next 30 days.

How do I fix CVE-2024-31999?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.